[4] The topography in the northern San Mateo Mountains is gentler than that in the south, but still features deep canyons, high ridgelines and generally dry conditions.

Winters are cold enough to bring snow, and during July and August, the desert "monsoon" season, rainwater may flood narrow canyons.

[5] Vegetation within the Wilderness Area ranges from mixed conifers, such as pine, spruce, fir, in the higher elevations, to pinion and juniper in the more open ground east of the mountains, to stands of ocotillo along the western banks of the Rio Grande.

[2] Habitats in the Withington Wilderness support populations of mountain lion, black bear, elk, mule deer, coyote, turkey and quail.

To the north of the Withington Wilderness and San Mateo Mountains is the Very Large Array radio telescope observatory.